Free Essay

Computer Network

In:

Submitted By nireesha
Words 263
Pages 2
ARP:
The Address Resolution Protocol (ARP) plays a key role in the process of IP routing. ARP finds the hardware Media Access Control (MAC) address of a host from its known IP address. ARP maintains a cache called ARP table in which Link-layer addresses (MAC address) are mapped to network-layer addresses (IP address).
How ARP works:
The capture of local traffic from my home network is shown below. At my home network my Home PC (source) IP address is 192.168.1.2 where as my default gateway (Home router) IP address is 192.168.1.1

Findings from the Capture:
Before a source sends a datagram to destination, it looks in its ARP table to check if there is a MAC address for the corresponding IP address of the destination. If there is no such entry in the ARP table, the source sends a Broadcast request to every single device on the subnet. Each device on the subnet compares the destination IP address to its own IP address. If the destination IP address match with the any of the device IP address in the subnet then only the matching IP address device gives a Unicast reply to the source with its MAC address. If the destination address is out of the subnet then the edge router (IP address of default gateway) will send a Unicast reply with its connected interface MAC address. The source then adds the destination MAC address to its ARP table encapsulates the datagram by adding header and trailer content, and proceeds to transfer the data.

Similar Documents

Premium Essay

Computer Networks

...North South University  School of Business MIS 105 Introduction to the Computer  Group Presentation   Summer 2012  Presentation Date:  05‐Aug‐2012 Sunday    Venue: Classroom         Time: Normal Class time       Out of: 30    Topic: Computer networks    Scenario: You work in the mid‐level management position of a large multinational  corporation handling millions of records per month. The corporation has about 10  different concerns with around 50 branches countrywide. The corporation has recently  decided to overhaul their computer network system in order to tune up their data  communication system. You, as in charge of the project, are to design a new networking  plan that will improve the performance of their existing data communication system.    What to do:  • Prepare a Multimedia presentation (Power Point) in your group that clearly  explains your plan. If you are planning to use any software/hardware you must  be very specific with their names and the way they work along with their success  history. You are required to perform an extensive online research for this  purpose. You may assume any other parameter that has not been mentioned in  the above scenario.  • You must reference every page (in‐text referencing) of your presentation in  Harvard style. Remember, your work do not have any value without appropriate  referencing. Your presentation must include at least 6 in‐text references; at least  2 of these must be from online or printed journals. You may download Harvard ...

Words: 531 - Pages: 3

Free Essay

Computer Network

...I. Computer Dynamics Computer Dynamics is a microcomputer software development company that has a 300-computer network. The company is located in three adjacent five-story buildings in an office park, with about 100 computers in each building. The current network is a poorly designed mix of Ethernet and token ring (Ethernet in two buildings and token ring in the other). The networks in all three buildings are heavily overloaded, and the company anticipates significant growth in network traffic. There is currently no network connection among the buildings, but this is one objective in building the new network. Describe the network you would recommend and how it would be configured with the goal of building a new network that will support the company’s needs for the next 3 years with few additional investments. Be sure to include the devices and type of network circuits you would use. You will need to make some assumptions, so be sure to document your assumptions and explain why you have designed the network in this way. Because we are considering the company present needs and over the next 3 years and not adding any addition investments, I would design the network using the traditional network design process. Computer Dynamics is centrally located in three adjacent five-story buildings, however there is no network connectivity amongst the buildings, which means we have to build a backbone to connect all three LANs. Before addressing the connectivity issues amongst the buildings...

Words: 460 - Pages: 2

Premium Essay

Computer Network

...Week 2 – Case Study SEC-280 11-9-2013 The first point that I will address consist on the multiple dangers that computer networks are exposed, that are in majority done by perpetrators that get access to servers of Windows and Linux to explode their vulnerabilities.. The use of these codes or malware in the form of viruses, worms, time bombs or any peculiar name this individuals use to give to their destructive toys, are a major concern to the protection of confidential information. Data so sensitive that in their majority is composing of identity, credit, and property information so well collected and compiler that is plenty for the creation of a clone of a company or a person. These identity theft atrocities are not limit to the software and information appropriation; also the attacks diminish computer performance, affecting their velocity and cause computers to crash. The CIO should possess a compendium of way’s to defend his network, and a rapid decision capability to take decisions in a short time period. Furthermore, in general terms security; as we can define “ the act of provide a sense or protection against lost, attack or harm”, can use or integrate a complete protection plan. Depending on the resources of the company the integration of a security plan that can integrate “the five pillars of security IT security operation: policy and audit management, access management, infrastructure and hardware security and incident response.” The real world presents to us a...

Words: 591 - Pages: 3

Premium Essay

Computer Networks

...| Computer Networks | By:Yaafiz Mohamed (S12425216)Zimna Ahmed (S12465436)Shahuma Abdulla (S12465351)Najudha Adam (S12465351)Sama Ali (S12465333) | | | | | Table of Contents Introduction 3 Computer and Networking. 3 Characteristics of Computer Networks. 3 Types of Computer Networks. 4  PAN (Personal Area Network) 4  LAN (Local Area Network) 5  MAN (Metropolitan Area Network) 5  WAN (Wide Area Network) 5  CAN (Campus Area Network) 5  SAN (Storage Area Network) 5 Why do we network our computers? 6 Peer-to-peer networking. 6 Computer Network Technologies 7 Conclusion: 8 Reference: 9 Introduction The purpose of the report is to survey and monitor the current state of computer network and the types of computer networks. This report is written by examining a range of recent published articles, magazine articles, and internet sites on the topic of computer networks used which are used commonly. The report is mainly about the types of computer network and their functions. Computer and Networking. A computer is a programmable machine, which is designed to sequentially and arithmetically carry out a sequence of logical operations. The particular sequence of operation allowing to solve more than one kind of problem. It responds to a specific set of instructions in a well defined manner. It can execute a pre-recorded list of instructions. Main components of computers are input, output and process. (Thakur) According to (Mitchell, What is (Wireless...

Words: 1669 - Pages: 7

Premium Essay

Computer Network

...Computer Network A computer network is a group of computers that are interconnected by electronic circuits or wireless transmissions of various designs and technologies for the purpose of exchanging data or communicating information between them or their users. Networks may be classified according to a wide variety of characteristics. This article provides a general overview of types and categories and also presents the basic components of a network. Introduction A computer network allows sharing of resources and information among devices connected to the network. The Advanced Research Projects Agency (ARPA) funded the design of the Advanced Research Projects Agency Network (ARPANET) for the United States Department of Defense. It was the first operational computer network in the world.[1] Development of the network began in 1969, based on designs developed during the 1960s. For a history see ARPANET, the first network. Purpose Facilitating communications Using a network, people can communicate efficiently and easily via e-mail, instant messaging, chat rooms, telephony, video telephone calls, and videoconferencing. Sharing hardware In a networked environment, each computer on a network can access and use hardware on the network. Suppose several personal computers on a network each require the use of a laser printer. If the personal computers and a laser are connected to a network, the personal computers users each can access the laser printer on the network, as they need...

Words: 3658 - Pages: 15

Free Essay

Computer Network Lab Manual

...Hubballi COMPUTER NETWORKING LAB Mahantesh Patil 2BV14IS410 Mahantesh Patil 2BV14IS410 CN LAB REPORT Dept. of ISE, BVBCET LAB-01 List the hardware components 1) Difference between switch and Hub: 2) Difference between SWITCH and ROUTER 3) Differences between Router and Gateway 4) What is the Difference between Subnetting and Supernetting? HARDWARE COMPONENTS Cables: 1|Page Mahantesh Patil 2BV14IS410 CN LAB REPORT Dept. of ISE, BVBCET Cables: which are used to connect one or more devices to computer or network. Different types of network cables are available market they are Coaxial cable, Optical fiber cable, Twisted pair cable. RJ-45 The most common UTP connector is RJ45 (RJ stands for registered Jack), as shown in Figure. The RJ45 is a keyed connector, meaning the connector, meaning the connector can be inserted in only one way. 2|Page Mahantesh Patil 2BV14IS410 CN LAB REPORT Dept. of ISE, BVBCET SWITCHES: Switches contain many ports to connect different network segments. They are similar to hubs, but offer greater performance. When a network contains a large number of devices, switches are needed instead of hubs to make sure the communications between devices does not slow down. Contrary to hubs, switches send the data it receives only to specific ports. NIC(NETWORK INTERFACE CARD) A network card, network adapter, or NIC is a piece of computer hardware designed to allow computers to communicate...

Words: 3647 - Pages: 15

Premium Essay

Computer Networks

...computer networks Table of Contents DECLARATION 2 INTRODUCTION 5 PURPOSE 5 NETWORK CRITERIA 6 Performance 6 Reliability 6 Security 6 TYPES OF NETWORK CONNECTION 6 NETWORK CLASSIFICATION 7 Connection method 7 Wired technologies 7 Wireless technologies 8 Scale 9 Personal Area Network 9 Local Area Network 9 Metropolitan Area Networks 10 Wide Area Network 10 Network Architecture 10 BASIC HARDWARE COMPONENTS 14 Network interface cards 14 Repeaters 14 Hubs 14 Bridges 15 Switches 15 Routers 15 Modem 16 CABLE STANDARD 16 Connectors and other information 16 Conductors required 17 Characteristics 17 ACCESS CONTROL METHODS 19 Token Based Access 19 Token priority 19 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) 20 Collision detected procedure 20 INTRODUCTION A computer network, often simply referred to as a network, is a group of computers and devices interconnected by communications channels that facilitate communications among users and allows users to share resources. Networks may be classified according to a wide variety of characteristics. A computer network allows sharing of resources and information among interconnected devices. In the 1960s, the Advanced Research Projects Agency (ARPA) started funding the design of the Advanced Research Projects Agency Network (ARPANET) for the United States Department of Defense. It was the first computer network in the World.  Development of the network...

Words: 5343 - Pages: 22

Premium Essay

Unit 7 Computer Networks

...CERTIFICATE/DIPLOMA IN IT COMPUTER NETWORKS R/601/7320 LEVEL 3 UNIT 7 GUIDED LEARNING HOURS: 60 UNIT CREDIT VALUE: 10 COMPUTER NETWORKS R/601/7320 LEVEL 3 UNIT 7 AIM OF THE UNIT This unit aims to give the learners an understanding of the key components, the network protocols and the services provided by network systems. Learners will develop skills required to ensure network security, gain an understanding to the functions of hardware and software components, the purpose, connections and connection devices and why network security is important. Networks are used not only in large organisations but in small businesses and homes. Learners will understand the types of network and the principles across LAN and WANs. They will understand the options for wired and wireless networks and the and appreciate the benefits and risks to businesses of a network. www.ocr.org.uk 2 Computer Networks Level 3 Unit 7 ASSESSMENT AND GRADING CRITERIA Learning Outcome (LO) Pass The assessment criteria are the pass requirements for this unit. Merit To achieve a merit the evidence must show that, in addition to the pass criteria, the learner is able to: Distinction To achieve a distinction the evidence must show that, in addition to the pass and merit criteria, the learner is able to: The learner will: 1 Know types of network systems and protocols The learner can: P1 describe the types of networks available and how they relate to particular network standards and protocols...

Words: 1844 - Pages: 8

Premium Essay

Threats to Computer Networks

...TABLE OF CONTENT Introduction 2 Threats 2 • State-sponsored espionage and sabotage of computer networks 2 • Monster DDoS attacks 2 • The loss of visibility and control created by IT consumerization and the cloud 2 • The password debacle 3 • The insider threat 3 UAE CASE 3 Precaution 4 Conclusion 4 Bibliography 5   Introduction As the requirement of the paper I will explain the types of fraud may face by the organisation computer networks. Along with I will discuss two cases of such fraud in UAE and finally I will discuss possible precautions to mitigate the risk of such frauds. In recent year the computer network threats become technically more advanced, sophisticated, more organised and at the same time difficult to detect. It is important to mention that these attacks not only damage network security for financial frauds but this also aim to disable and reliability of the infrastructure as well, which may cause worse type of threat to the national security. (Tom Cross and Eric Savitz, Forbes Staff, 2012) Threats Most respected financial magazine FORBES has mentioned five main security threats to the computer networks which includes. • State-sponsored espionage and sabotage of computer networks o In 2012 a very famous virus called Flame was discovered which was not traced by the software in years. Similarly virus named Shamon destroyed the data of oil and energy companies and made the machines unbootable. • Monster DDoS attacks o DDos stands for the...

Words: 1014 - Pages: 5

Premium Essay

Threats and Attacks to Computer Network

...Chapter 4 Threats and Attacks to a Computer Network Research shows that “threats to the computers and networks have been an issue since computers began to be used widely by the general public. Nowadays, any computer or network that is connected to the Internet is at risk” (http://infopeople.org/resources/security/basics/threats_vulnerabilities.html, 2008) There are unlimited different types of threats exists in computer networking field but in this report mainly six different common but important threats were discussed. 4. 1 Spoofing Spoofing is a technique used to hide identity of traffic originator or assume identity of trusted entity or fooling a computer into believing which actually you are not. The most common spoof is email where a hacker pretend to be a different internet address from the one you have just to gain his/her credit card no, passwords, personal information or to theft any identity. Spoofing normally involves sending many packets/messages pretending to be a real legitimate person and spoofed IPs are very hard to back track. There are many different types of spoofing, such as ▪ IP addresses, MAC addresses changing attacks ▪ Link alteration ▪ DNS server spoofing attack ▪ Content theft ▪ E-mail address changing attack 4.2 How Penetration Attack Works? Penetration attack is basically to an attempt to break the security features of a system in order to understand the system or system design and implementation. The main purpose of penetration...

Words: 934 - Pages: 4

Premium Essay

The Role of Computer Networks in Smb Operations

...micro-employing less than 6 people, medium-employing 6-9 people and small businesses-between 10 and 29 employees. In terms of activities they are mostly engaged in retailing, trading or manufacturing and education. In Ghana SMBs have been noted as the engine of growth by the National board for small scale industries through the provision of employment and income. They represent about 92% of Ghanaian business and contribute about 70% to Ghana’s GDP and over 80% to employment (Ghana statistical service 1998). Information is needed and distributed every day in businesses. Every business start with high hopes of success but with inaccurate data and the wrong means of transferring this information may lead to the sudden collapse of the business. Computer network is one tool owners of businesses can utilize to gain access to accurate information and transfer those information generated at rapid speed. Data generation, dissemination and storage are at the...

Words: 10202 - Pages: 41

Premium Essay

Computer and Network Security

...Windows NT (CVE, 2013). In the first article it discusses the use of USB devices in the workplace. USB’s are used for transporting data from one computer to another. These allow for business requirements to be reached at a faster pace but they also pose a number of security challenges. Those challenges may be “disgruntled workers, careless users and malicious individuals” (Couture, 2009, p. 6). Ways to migrate this issue is by gluing shut the ports, disable USB ports in BIOS, prevent users from installing a USB device by denying permission on files called usbstor.pnf and usbstor.inf, making USB ports read only, disable USB ports in Group Policy, or disable Autorun (Couture, 2009, p. 11). In the second article it discusses the vulnerabilities of the BIOS. The BIOS performs power up test amongst the hardware components and memory and without this program the computer wouldn’t know what to do after it was turned on. The BIOS can be accessed by the use of backdoor passwords, cracking the BIOS password, deleting the contents of the CMOS RAM by software and/or hardware (Allgeuer, 2001, p. 4). Ways to mitigate the risk of users accessing the BIOS is to use BIOS passwords to protect the BIOA configuration utility, for the more critical systems different BIOS password should be used than less critical systems, boot only from hard drives, computer cases should be...

Words: 1760 - Pages: 8

Premium Essay

Computer and Network Security

...Computer and Network security Problem statement Unauthorized Access “As the threat of unauthorized access grows companies and people continue to look for security to upgrade.” (Howard, 2009)``Unauthorized access'' is a very high-level term that can refer to a number of different sorts of attacks. The goal of these attacks is to access some resource that your machine should not provide the attacker. For example, a host might be a web server, and should provide anyone with requested web pages. However, that host should not provide command shell access without being sure that the person making such a request is someone who should get it, such as a local administrator. What network security is The history of network security “Sense the 1980’s networks have become more complex, so the need for security has become more complex.” (Mowers, 2006) The need for network security is a relatively new requirement. Prior to the 1980s most computers were not networked. It was not due to lack of desire to network them; it was more a result of the lack of technology. People or organizations could be interconnected over the shared network. It was no longer necessary to connect systems in a point-to-point configuration. Vulnerabilities were introduced with the deployment of this distributed environment utilizing shared, packet switched networks employing protocols such as TCP/IP and the concept of trusted systems. Systems on the network "trusted" each other. This situation was frequently...

Words: 1474 - Pages: 6

Premium Essay

Computer Network & Information Security

...has focused on computer security of big businesses and how they have been breached, yet individuals do not stop and think about their own personal computer safety. Information can be stolen or damaged, access of personal computers can be gained without permission, viruses and worms can enter creating problems for a user, and our computers may be susceptible to cyber-attacks from hackers. Yet most computer users are new to the technology or do not realize the dangers at hand. This is why users need to learn how to keep their personal computer safe. To achieve a good level of security, there are many important elements that must be taken into account: authentication, access control, data integrity, content protection, etc. Information security can be obtained using methods such as cryptography and network protocols. Computer security is the process of detecting unauthorized use of your computer or PC. As the old saying goes “prevention is better than cure”, according to this we realize that if we learn about the possible loopholes in the security, then we can prevent it from occurring in the first place. But the big question is 'why should I care about my computer security?’. We use computers for everything from banking and investing to shopping and communicating with others through email or chat programs. Although we may not consider our communication a 'top secret', but you don’t want others to eavesdrop on you conversations, read your mails, use your computer to attack others...

Words: 1454 - Pages: 6

Free Essay

Evaluating the Security of Computer Networks

...Evaluating the Security of Computer Networks Security in Systems Architecture and Applications SE579 2 Table of Contents Evaluating the Security of Computer Networks I. Vulnerabilities A. Design Flaws B. Poor Security Management C. Incorrect Implementation II. Firewalls A. Packet Filtering B. Circuit Level Gateway Proxy Server C. Application Gateway III. Antivirus A. Scans IV. Intrusion Detection Systems V. Disadvantages VI. Conclusion 3 One of the major computing challenges in today’s economy is the lack of adequate security over the information computer networks, and internet applications in which business, government, and economy depend on. Businesses have become more dependent on information. The gathering, organizing, managing, finding, and analyzing of information are crucial to businesses. Computer viruses created by hackers cost businesses $55 billion in 2003. In 2011, a single instance of hacking on the Play Station cost Sony more than $170 million, while Google lost $500,000 due to hacking in 2005.(Coyne) 2003 Single instances of hacking may cost as much as $600,000 to $7m a day for...

Words: 2281 - Pages: 10